1992 Seville STS Chassis Dyno

Went down to Team Dynotech in Garland and had a real chassis dyno run to try to understand the home dyno results better. Looks worse than I expected, at 164.5 hp at the wheels. It appears that the car is either not getting enough spark or fuel in third gear. The expectation is that the third gear numbers would be greater than the 2nd gear max of 164 hp. Instead, third gear tops out around 160 on this chart, and at 156 hp on the 3rd gear only charts.

Right now I am maxxing at 164/.8= 205 hp to 164.5/.75=219 hp at the crank in second gear.

The first gear run was throttled down in order to avoid the 1/2 shift; first time through the car jumped on the dyno wheels -- quite exciting. (note the print is askew, not the scan)

 

Third Gear Data:

Third gear is direct (1:1). Normally third would have the best dyno rating. Third gear is topping out at 156 hp, down from second gear which is odd. If you look above on the 1/2/3/4 chart, then you see the peak for 3 was just above 160 hp.

I also think there is some difference in the car's acceleration if the PRNDL is set to Overdrive compared to 3. Using the G-techpro, Overdrive is always faster than 3, even though this seems counter-intuitive.

Here is an Engine dyno from Cadillac Drivetrain for the Northstar:

 

and finally here is a comparison of my 4.9 with a Northstar, assuming a 20% transmission loss for the Northstar. Note that the 4.6 DOHC Northstar will rev on to 6000 rpm, since it is a heavy breather, and the 4.9 OHV redlines at 4800 rpm. So this comparison is only interesting as "pull at RPM" and not absolute power: